Modelling soil physical behaviour with particular reference to soil science

Richards, B G; Peth, Stephan

doi:10.1016/j.still.2008.07.022

Cited by 27 publications

(9 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The soil environment is influenced by the state of three soil phases (solid, liquid and gaseous) and by a complex equilibrium among them, within which a number of different physical and chemical processes control the mechanical behavior of the soil (Richards & Peth, 2009). The mechanical property of soil in loading and unloading presents an elastic and plastic deformation with a nonlinear variation (Upadhyaya et al, 2002).The comprehensive expression of the stress-strain behavior of agricultural soils is complex and difficult to describe with a simple relationship.…”

Section: Soil Modelmentioning

confidence: 99%

Soil-blade orientation effect on tillage forces determined by 3D finite element models

Ibrahmi

Bentaher

Maalej

2014

Span. j. agric. res.

View full text Add to dashboard Cite

This paper investigated the effect of the cutting parameters of a blade on the tillage force components using finite element modeling. A three-dimensional model was carried out with Abaqus Explicit in order to study the interaction between the tool and soil. The soil was modeled with linear forms of the Drucker-Pager model, while the tool was considered as a rigid body with a reference point taken at its tip. The effect of tillage depth and the width of a vertical blade were studied. It was found that the amounts of the draught and vertical forces increase linearly with a slope of 0.037 and 0.0143 respectively when the width increases. The narrow tool (width < 60mm) has a greater effect on the specific draught force than a larger tool. Draught and specific draught force increase with polynomial and linear curve respectively versus the depth. However, this effect was reduced for the vertical force. These results were in a good agreement with previously published works. The second part of this paper is focused on the oblique position of the blade to evaluate the effect of the attack angles on both the tillage forces (draught, lateral and vertical) and the cutting process of the soil during and after its failure. For all considered angles, the draught force presents the highest values compared to the vertical and lateral forces. Results showed that working with small cutting and an average rake angles (30°to 60°and 45°respectively) can produce a good soil inversion.Additional key words: FEM; oblique blade; force; attack angles.* Corresponding author: ayadi.ibrahmi@yahoo.fr; ayadiibrahmi@hotmail.fr Received: 16-02-14. Accepted: 10-10-14.Abbreviations used: CFD (computational fluid dynamics); DEM (discrete element method); FEM (finite element method); RF (reaction force); RF2 (vertical force); RF3 (draught force); α (cutting angle); θ (rake angle).

show abstract

Section: Soil Modelmentioning

confidence: 99%

Soil-blade orientation effect on tillage forces determined by 3D finite element models

Ibrahmi

Bentaher

Maalej

2014

Span. j. agric. res.

View full text Add to dashboard Cite

show abstract

“…Johnson and Burt, 1990;Koolen et al, 1992;Lamandé et al, 2007). Richards and Peth (2009) reported large effects of the soil stiffness of a 20 cm thick plough pan on stress propagation. However, Lamandé and Schjønning (in press-a) reported that the stiffness of a relatively thin (5 cm) plough pan, although higher than that of the underlying soil, was of the same order of magnitude as in the underlying soil.…”

Section: Theoretical Evaluation Of the Upper Model Boundary Conditionmentioning

confidence: 99%

Challenges in the development of analytical soil compaction models

Keller

Lamandé

2010

Soil and Tillage Research

View full text Add to dashboard Cite

“…[3] Rigidity may possibly be valid for fractured rocks system [e.g., Peters and Klavetter, 1988;Therrien and Sudicky, 1996;MacQuarrie and Mayer, 2005]; however, in most natural soils the pore system is dynamically changing due to swelling and shrinkage depending on the water contents and due to soil biota activities among other factors [e.g., Horn, 2004;Richards and Peth, 2009]. Such changes in pore volume and pore size distribution including deformations in pore geometry result in the occurrence of separate porosity compartments.…”

Section: Introductionmentioning

confidence: 99%

Dual‐permeability model for flow in shrinking soil with dominant horizontal deformation

Coppola

Gerke

Comegna

et al. 2012

Water Resources Research

View full text Add to dashboard Cite

In this study, a dual‐permeability approach is discussed for modeling preferential flow in shrinking soils by accounting for shrinking effects on macropore and matrix domain hydraulic properties. Conceptually, the soil is treated as a dual‐permeability bulk porous medium consisting of two dynamic interacting pore domains: (1) the fracture (from shrinkage) pore domain and (2) the aggregate (interparticles plus structural) or matrix pore domain. The model assumes that the swell‐shrink dynamics is represented by the inversely proportional volume changes of the fracture and matrix domains, while the overall porosity of the total soil, and hence the layer thickness, remains constant. This assumption can be justified for soils with dominant horizontal soil deformation in the swelling‐shrinkage process (shrinkage geometry factor,rs> 3). The swell‐shrink dynamics was included in a one‐dimensional dual‐permeability model in which water flow in both domains was described with the Richards' equation. Swell‐shrink dynamics was incorporated in the model partly by changing the coupled domain‐specific hydraulic properties according to the shrinkage characteristics of the matrix and partly by allowing the fractional contribution of the two domains to change with the pressure head. As a first step, the hysteresis in the swell‐shrink dynamics was not included. We also assumed that the aggregate behavior and its hydraulic properties depend only on the average aggregate water content and not on its internal real distribution. The model proved, describing successfully effects of shrinkage on the spatial and temporal evolution of water contents measured in a silty loam soil in the field.

show abstract

Modelling soil physical behaviour with particular reference to soil science

Cited by 27 publications

References 19 publications

Soil-blade orientation effect on tillage forces determined by 3D finite element models

Soil-blade orientation effect on tillage forces determined by 3D finite element models

Challenges in the development of analytical soil compaction models

Dual‐permeability model for flow in shrinking soil with dominant horizontal deformation

Contact Info

Product

Resources

About